This invention relates to a composition for use on fibers. More particularly, this invention relates to a fiber treatment composition that produces fibers having excellent smoothness and antistick performance and to a composition which exhibits excellent dispersion stability.
Because of their excellent heat resistance and lubricity, dimethylpolysiloxane oils have become widely used as neat fiber treatment agents (the term "neat" denotes a treatment agent that contains 100% fiber treatment agent and does not contain solvent or water) for mechanical sewing thread and highly elastic polyurethane fibers (i.e. spandex). For example, in Japanese Patent Application Laid-Open No. 50-78695 (78,695/1975) it is disclosed that the smoothness and antistick character of fibers can be improved through the combined used of a dimethylpolysiloxane oil and the metal salt of a higher fatty acid.
However, because dimethylpolysiloxane oils and higher fatty acid metal salts are completely incompatible, the dispersibility of the higher fatty acid metal salts in the above types of compositions is very poor, and sedimentation occurs immediately when this type of composition is allowed to stand. The addition of a suspension agent to these types of compositions has been a method for improving the dispersibility, but the use of a suspension agent is also problematic because it reduces the lubricity of the treated fiber.
Pretreatment of the higher fatty acid metal salt with an organic solvent, such as a low-molecular-weight alcohol, has been disclosed for the purpose of improving the dispersion stability, for example in Japanese Patent Application Opening No. Hei 3-500183 (500,183/1991) WO90/00581, but this method is compromised by its use of an organic solvent, which raises the risk of air and water pollution, ignition or detonation, and human toxicity.
Japanese Patent Application Publication No. Sho 63-12197 (12,197/1988) discloses a fiber treatment composition that contains an organopolysiloxane resin. The neat lubricant is a composition comprising dimethylpolysiloxane oil, a particular organopolysiloxane resin, and a higher fatty acid such as stearic acid. However, because this composition contains a higher fatty acid, the corresponding smoothness is quite susceptible to variation in response to changes in temperature and sticking between the treated fibers also tends to occur quite readily.